1. Field of the Invention
The present invention relates to image forming devices, such as printers, facsimile machines, and copy machines, and to a sheet feeding device that supplies sheets to an image forming device.
2. Description of the Related Art
Various image forming devices are well known for use with personal computers and the like. Examples of image forming devices include laser printers, ink jet printers, facsimile machines, and copy machines. Image forming devices are often provided with a sheet-supply cassette for housing sheets, which are the subject of printing operations. The sheet-supply cassette supplies the sheets to the image forming device.
Japanese Utility-Model-Application Publication No. SHO-60-50630 describes a type of detected portion for indicating the size of sheets stacked in a sheet-supply cassette of a copy machine. The copy machine includes a cassette mount for receiving insertion of the sheet-supply cassette. The cassette mount includes a sensor and an actuator disposed adjacent to an outer side surface of the sheet-supply cassette. The outer side surface of the sheet-supply cassette is formed with alternating and equidistant protrusions and indentations aligned in the direction the sheet-supply cassette moves when inserted into the cassette mount. An independent size setting member is provided with protrusions with size and interspacing that correspond to the indentations on the side wall of the sheet-supply cassette. The protrusions of the size setting member can be inserted into the indentations on the sheet-supply cassette to fill in the indentations. The user fits the protrusions of the size setting member into the indentations of sheet-supply cassette at a position shifted according to the size of sheet housed in the sheet-supply cassette. When the sheet-supply cassette is inserted into the copy machine, the actuator moves in and out of the indentations of the sheet-supply cassette, turning the sensor on and off accordingly. Because the actuator does not move into the indentations of the sheet-supply cassette that are filled in with the protrusions of the size setting member, the copy machine can determine the type of sheet in the sheet-supply cassette by the on/off signal from the sensor.